Prescription eyewear to be used within masks without interfering with the functioning of the mask has been a source of difficulty and the subject of many design attempts over the years. For the most part, these attempts have sought to assemble an eyeglass frame inside the mask as a part of the mask. See, for example, Schutz et al., U.S. Pat. No. 2,388,713 of Nov. 13, 1945; Rodenhouse, U.S. Pat. No. 2,905,172 of Sep. 22, 1959; Waldherr, U.S. Pat. No. 4,023,214 of May 17, 1977 and Erickson et al., U.S. Pat. No. 7,677,724 of Mar. 16, 2010. Routine use of frame designs for incorporation in masks is not achievable with these designs. By routine use is meant wearing of the prescription eyewear for general purposes. For example, the eyewear may be routinely used with other optical devices such as inside the eyepiece of such devices as in the case of periscopes.
The term eyewear as used herein includes frames which may carry lenses, for example, prescription lenses, which can be used within or outside an air breathing mask without interference with the operation of the mask. An air breathing mask enables the wearer to work in noxious gas environments or under water, for example as a scuba mask.